Outsmart pesky fruit flies with handy-dandy trap

by Clay Thompson - Apr. 23, 2011 12:00 AMThe Arizona Republic

Today's question:

Recently, I had to go out of town for five days on business. I neglected to empty the garbage can in my kitchen before I left. When I came home and opened the garbage can, a cloud of tiny flies flew out. Were they fruit flies? Where did they come from?

Yes, they were fruit flies. They came from almost anywhere.

Until around the middle 1700s, people believed in something called spontaneous generation.

They thought that flies and other vermin, even mice, spontaneously emerged from rotting meat or dirty clothes or garbage or even dirt.

Even Aristotle believed this, which just goes to show you the ancient Greeks weren't always so smart.

Anyway, fruit flies are so small they can get in through your screen door or by crawling under the door. Or maybe some eggs came home with you from the grocery store on a piece of less-than-fresh fruit.

Even if you have a tight-fitting lid on your garbage can, they could probably get in anyway.

Scientists who study genetics love fruit flies because they lay hundreds of eggs that hatch in just a few hours and the adults only live 10 days or so. And they have big chromosomes. That makes them useful for the study of mutations.

Fruit flies feed on the yeast created when fruit or garbage ferments. They eat the slime in your drains. They can even process alcohol fumes before the stuff kills them.

Here's how to get rid of them: Take a jar you don't need anymore and drop in a few banana slices. Cover the top with plastic wrap secured with a rubber band and poke a couple of really tiny holes in the plastic.

The fruit flies can get in - they have an excellent sense of smell - and can't find their way out. They may have large chromosomes, but they're not all that smart.